Sheet-feed for printing presses

ABSTRACT

A sheet feed for printing presses, in particular for offset presses, has a pile table located between feed side walls. The pile table receives a pile of sheets thereon and it is vertically movable with a main pile lifter. An auxiliary pile lift is provided for uninterrupted sheet delivery when a new pile of sheets is inserted. The auxiliary pile lift has non-stop rails for inserting non-stop rods supporting a residual sheet pile. One vertically movable lift component of the auxiliary pile lift, which is separate from the main pile lift, is disposed on each of the outsides of the two feed side walls. The non-stop rails--optionally together with the lift components--form a frame, which surrounds the feed side walls --or at least portions thereof--on the outside.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to a sheet feed for printing presses, inparticular offset presses, having a pile table for receiving a pile ofsheets thereon, the pile table being located between feed side elementsand being vertically movable by means of a main pile lifter, and havingan auxiliary pile lift for uninterrupted or so-called non-stop sheetdelivery when a new pile of sheets is placed therein, the auxiliarysheet lift having non-stop rails for coordinating non-stop rods or thelike supporting a residual sheet pile.

Sheet feeds in printing presses serve to separate sheets from a pile ofsheets and deliver them to the printing mechanism of the printing press.Because the height of the sheet pile decreases as the withdrawal ofsheets progresses, the pile is located on a vertically movable piletable, so that as the pile height decreases, the pile table can be movedcorrespondingly upwardly, so that the topmost sheets remain within anoperative range of a suction head arrangement which takes the sheetsfrom the pile and delivers them to the sheet transport path of theprinting press. To assure uninterrupted sheet delivery, a so-calledauxiliary pile lift is provided, which receives the residual sheet pileleft over from a pile of sheets during the delivery of a new sheet pile.The new sheet pile is placed beneath the residual sheet pile, and theresidual sheet pile and the new sheet pile are then combined.

Sheet feeds in printing presses are known in which the pile table whichreceives the main pile is suspended from support chains which are drivenvia sprocket wheels. The suspension of the support chains is effectedvia deflector sprocket wheels, which are supported on a crossbardisposed above the sheet pile. Because of the crossbar, the structure isvery high, and the view of the paper stream is obstructed.

So-called compact feeds are therefore also known, in which the structureis somewhat lower, because a crossbar is not required. Instead, feedside walls facing one another at a spaced distance are provided, betweenwhich the sheet pile is deposited on a pile table. The pile table restson vertical guides which are disposed on inner sides of the feed sidewalls. At the same time, above the pile table, these vertical guidesreceive lift slide blocks of an auxiliary pile lift; that is, the mainpile lift and the auxiliary pile lift both use the same vertical guides.As a result, however, the vertical guides must be relatively long andhence must extend to a corresponding height, because even if the piletable lift slide block is moved far upwardly, there must still be anavailable region of the guide above this lift slide block in order toreceive the lift slide blocks of the auxiliary pile lift. Moreover, itis necessary for the non-stop rails secured to the lift slide blocks ofthe auxiliary pile lift to be bent downwardly at a right angle, so thatnon-stop rods to be placed thereon will stay at the correct workingheight for the residual sheet pile. However, the fact that the guidesprotrude relatively far upwardly leads to the same disadvantages thatexist in sheet feeds with crossbars; that is, both the accessibility andthe view are hindered; for an operator standing on an operator platforminstalled to the side of the feed side wall located on the side of theoperator, the view of the paper stream is obstructed. Moreover, the highstructural form causes problems in terms of achieving accidentprevention.

SUMMARY OF THE INVENTION

It is therefore the object of the invention to create a sheet feed of acompact structural form, which has relatively small height dimensionsand a simple construction and which in particular provides freeaccessibility and viewability for an operator. The low height of thesheet feed also leads to continuous press design; that is, the feed andprinting mechanisms can be adapted to the corresponding structuralheights of the printing press, and the feed, which has a greatconstruction-dictated height in the prior art, does not disturb thepress design.

According to the invention, this object is attained in that onevertically movable lift element of the auxiliary pile lift, which isseparate from the main pile lift, is disposed on each of the outsides ofthe two feed side elements, and that the non-stop rails, optionallytogether with the lift elements, form a frame, which surrounds the feedside elements or at least portions thereof, on the outside. According tothe invention, the elements of the auxiliary pile lift are thus disposedon the outsides of the feed side elements, and as a result, a completedecoupling from the main pile lift exists. The feed side elements arepreferably formed as feed side walls. The main pile lift may, forexample, have vertical guides which are disposed on the insides of bothfeed side walls. Guide elements of the vertically movable lift elementsof the auxiliary pile lift are conversely provided on the outsides ofthe two feed side walls, so that the main pile lift and auxiliary pilelift cannot hinder one another, and an overlapping of elements of themain pile lift with those of the auxiliary pile lift is possible, sothat a sheet feed with only a very slight structural height isattainable. As a consequence, an unimpeded free view of the paper streamfrom the operator side is possible, particularly from an operatorplatform installed in the region of the feed. In order to create bearingsurfaces for non-stop rods on the front and rear side of the sheet pile,the lift elements bear a frame, or form parts of this frame, whichsurrounds the feed side walls, or at least portions thereof, on theoutside. The front and rear sides of this frame form the non-stop railswhich support the non-stop rods. If the frame does not completelysurround the feed side walls on the outside but rather protrudes throughcorresponding slits in the feed side walls, then only portions of thefeed side walls are received in the frame. The invention also makespossible a continuous or through press design, and in particular therealization of a feed form or shape which is likewise contoured andsmooth in much the same manner as that of the printing units.

In a further feature of the invention, as already noted, the liftelements can be supported in guides, which are secured to the outsidesof the feed side elements. These are preferably roller guides, with therollers supported on the lift elements and running in guide railssecured to the outsides of the feed side elements.

It is advantageous if the lift elements are secured to support chains,which are driven by means of sprocket wheels, disposed on the outsidesof the feed side elements. At least one of the sprocket wheels of eachfeed side element forms a drive sprocket wheel, and the other sprocketwheels are embodied as deflector sprocket wheels for the associatedsupport chain. The two drive sprocket wheels of the two feed side wallsare preferably disposed in a manner fixed against relative rotation on acommon drive shaft. This drive shaft is operatively connected with adrive mechanism, in particular an electric motor. In a further featureof the invention, it is provided that on the side of the sheet feedtoward the printing press, the associated portion (front non-stop rail)of the frame protrudes through apertures in the feed side walls. Thisassures that the front non-stop rail comes to rest in front of thecorresponding side of the sheet pile, or in other words between thesheet pile and the printing mechanism of the printing press.

On the side of the sheet feed toward the printing press, the associatedportion (rear non-stop rail) of the frame is embodied removably. Thusaccess is unobstructed once the rear non-stop rail is removed.

Preferably, the rear non-stop rail is U-shaped, and its two legs extendapproximately parallel to and spaced apart from the outsides of the feedside walls. The rib placed between the two legs of the U-shaped rearnon-stop rail covers the face ends of the feed side walls. It isaccordingly unnecessary to have apertures in the feed side walls here.

It is advantageous if the outsides of the feed side walls are covered bycoverings, which have slits on their face ends for the emergence of thelegs of the rear non-stop rail. These coverings are needed for the sakeof accident prevention; they cover the chain drives of the auxiliarypile lift. The slits in the coverings, through which the legs of therear non-stop rail extend, are quite narrow and have close tolerances,so that there is no danger of injury to a human operator.

Preferably, a point connecting the removable rear non-stop rail to theremainder of the frame is located under or substantially under thecovering. As a result, no elements protrude from the coverings once therear non-stop rail is removed.

The guides of the lift elements extend maximally up to the upper edge ofthe feed side walls. Preferably, they end even before the upper edge, sothat the feed side walls close off the sheet feed at the top withoutprotruding parts or the like. For the sake of favorable forcedistribution, and to counteract a danger of jamming if the frame isslightly skewed, the front non-stop rail is secured in floating fashionto the remainder of the frame. The removable rear non-stop rail alsopermits a given skewing. The connecting point with the lateral frameelements affords the necessary motion.

Preferably, the legs of the rear non-stop rail are embodied as hollowprofile sections, which can be slipped onto receiving mandrels of thelift elements. This makes simple removal and mounting of the rearnon-stop rail possible.

The drawings illustrate the invention in terms of an exemplaryembodiment; specifically, they show:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1, a schematic perspective view of a sheet feed;

FIG. 2, a side view of the sheet feed; and

FIG. 3, a plan view (partly in section) of the sheet feed.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1--schematically--shows a sheet feed 1 of a printing press--notshown. The sheet feed 1 has two feed side components formed as walls 2and 3, spaced apart parallel from one another, between which avertically movable pile table 4 of a main pile lift 5 is disposed.Components of an auxiliary pile lift 8, which has a frame 9, aredisposed on the outsides 6 and 7 of the feed side walls 2 and 3. Theframe 9 has a rear non-stop rail 10, which is U-shaped, and its two legs11 and 12 extend approximately parallel to and spaced apart from theoutsides 6 and 7 of the feed side walls 2 and 3. The rib 13 locatedbetween the two legs 11 and 12 of the rear non-stop rail 10 covers theface ends 14 and 15 of the feed side walls 2 and 3. Also, on the side ofthe sheet feed 1 toward the printing press, the frame 9 has a frontnon-stop rail 16, which extends through apertures 17 and 18 in the feedside walls 2 and 3.

A sheet pile 19 can be disposed on the pile table 4 between the feedside walls 2 and 3. The bearing face 20 of the pile table 4 haslongitudinal indentations 21, extending in the direction of the feedside walls 2 and 3, which serve--as in the auxiliary pile mode--toreceive non-stop rods 22. The mode of operation will be described infurther detail hereinafter.

FIG. 2 shows a side view on the feed side wall 2 and on the elementsassociated with this feed side wall 2 of the auxiliary pile lift 8. Thefollowing description applies correspondingly to the embodiment of thefeed side wall 3 and the parts of the auxiliary pile lift 8 locatedthere, so that it will suffice to describe only the feed side wall 2 ofFIG. 2.

A roller guide 23 is disposed on the outside 6 of the feed side wall 2;it has a U-shaped guide rail 24, in which rollers 25 of a verticallyrotatable lift element 26 of the auxiliary pile lift component or 8 aresupported. The U-shaped guide rail 24 is screwed by its back rib to theoutside 6 of the feed side wall 2. The rollers 25 are supportedrotatably on the lift component or element 26, so that the latter issupported, movable vertically up and down, on the outside 6 of the feedside wall 2. The lift element 26 is covered along the roller guide 23 bya securing rib 27, which is retained on the outside 6 of the feed sidewall 2 by means of spacer bolts 28. Located laterally next to the guiderail 24 on the lift element 26 is a securing point 28 a support chain29, which is wrapped in a closed loop around sprocket wheels 30. One ofthe sprocket wheels 30 is located at the upper end laterally next to theguide rail 24. It forms a deflector sprocket wheel 31. A further one ofthe sprocket wheels 30, also embodied as a deflector sprocket wheel 32,is located--below the deflector sprocket wheel 31--in the region of thelower end of the roller guide 23. Quite close to the deflector sprocketwheel 32 is a further one of the sprocket wheels 30, embodied as adeflector sprocket wheel 33. Finally, offset laterally from thedeflector sprocket wheel 32 in the direction toward the printing press,there is the sprocket wheel 30, which forms a drive sprocket wheel 34.All the sprocket wheels 30 are located on the outside 6 of the feed sidewall 2, and they are disposed such that the loop of the support chain 29forms a "double" L. For tensioning the support chain 29, the deflectorsprocket wheel 32 is secured to a slide block 35, which is movableparallel to the roller guide 23 and can be fixed by means of a screw 36.

FIG. 3 shows that the two sprocket wheels 34 of the two feed side walls2 and 3 are disposed in a manner fixed against relative rotation on acommon drive shaft 37, which is located between the sheet pile 19 andthe printing mechanism, not shown, of the printing press. A servo-motor38 has a sprocket wheel 40, which is connected via an adjusting chain 41to a sprocket wheel 42 which is disposed on the drive shaft 34 in amanner secured against relative rotation. Both the servo-motor 38 andthe sprocket wheels 40 and 42, as well as the adjusting chain 41, aredisposed between the two feed side walls 2 and 3.

Lift slide blocks 45 and 46 are supported vertically movably on theinsides 43 and 44 of the feed side walls 2 and 3 and are joined to thepile table 4 (not shown in FIG. 3). Via lifting chains 47 and 48 andother driving and deflector elements, not shown, the lift slide blocks45 and 46 can be displaced in accordance with the desired position ofthe pile table 4.

The lift element 26 has an arm 49 and a receiving mandrel 50; the arm 49extends as far as a slit-like aperture 17 in the feed side wall, and thereceiving mandrel 45 extends up to the level of the face end 14 of thefeed side wall 2. The front non-stop rail 16 is secured in floatingfashion to one face end 52 of the arm 49. For that purpose, a shim 54and a bushing 55 are secured to the face end 52 by means of a screw 53,and the front non-stop rail 16 receives the bushing 55 in a bore 56which has a diameter greater than the diameter of the bushing 55. Thethickness of the front non-stop rail 16 is less than the length of thebushing 55, so that the overall result is a floating connection betweenthe arm 49 and the non-stop rail 16.

End switches 57 are disposed in the upper and lower regions of theslitlike aperture 51; they cooperate with an actuation plate 58 of thefront non-stop rail 16. The end switches 57 turn off the servo-motor 38when the uppermost or lowermost position of the lift element 26 andhence of the frame 9 has been reached.

The rear non-stop rail 10 is formed as a hollow profile section 59,which can be slipped into the receiving mandrel 50 of the lift element26. The receiving mandrel 50 has a wedge-like shape, so that a tiltingmotion of the hollow profile section 59 is possible so that a pin 60protruding from the receiving mandrel 50 can enter into a receiving bore61 of the hollow profile section 59 to prevent it from being pulled off.Swiveling the hollow profile section 59 upwardly causes the pin 60 toemerge from the receiving bore 61, and the hollow profile section 59, orin other words the rear non-stop rail 10, can now be removed.

The two outer sides 6 and 7 of the feed side walls 2 and 3 are coveredby covers 62 and 63, which cover the drive elements and so forth of theauxiliary pile lift 8 and which have slits 64 on their face ends, fromwhich the rear non-stop rail 10 protrudes. The connecting point 65between the rear non-stop rail 10 and the respective lift element 26 islocated under the applicable covering 62 or 63.

The sheet feed according to the invention functions as follows:

It is assumed at the outset that a sheet pile 19 is placed between thefeed side walls 2 and 3 (FIG. 1). The non-stop rods 22 shown thereat,and the rear non-stop rail 10 as well, are assumed to be removed. It isalso assumed that a suction head arrangement, not shown, takes therespective uppermost sheet from the sheet pile 19 and delivers it to theprinting press, in the direction of the arrow 66 (FIG. 1). This causesthe pile height to decrease, which is detected by a sensor whichactuates the main pile lift and, as a result, the pile table 4 and hencethe sheet pile 19 move incrementally upwardly. The instant there is onlya small height of the sheet pile 19 remaining, a human operator slidesthe non-stop bars 22 into the longitudinal indentations 21 and thenactuates the auxiliary pile lift 8, so that the frame 9 moves upwardly,and the rear non-stop rail 10 and the front non-stop rail 16 both movefrom below towards the protruding ends of the non-stop rods 22. In thisway, a residual sheet pile is located on the non-stop rods 22 and can bereplenished as operation continues by means of the auxiliary pile lift8, at the rate of sheet removal. At the same time, by actuation of themain pile lift 5, the pile table 4 is moved downwardly and a new sheetpile is introduced. This new sheet pile 19 is then raised, so that itcomes to rest with its top just below the non-stop rod 22.

Next, the non-stop rods 22 can be pulled out by the human operator, sothat a new complete pile is formed. The above description shows that, asa result, uninterrupted sheet delivery is possible.

I claim:
 1. A sheet feed for a printing press, comprising:a pile tablefor supporting thereon a pile of sheets, and feed side componentslaterally bounding said pile table; a main pile lift for verticallymoving said pile table; and an auxiliary pile lift for facilitatinguninterrupted sheet delivery to the printing press when a new pile ofsheets is inserted at said pile table; said auxiliary pile liftincluding non-stop rails and non-stop rods supported in said non-stoprails, said non-stop rods bearing a residual sheet pile; said auxiliarypile lift further including vertically movable lift components separatefrom said main pile lift, one of said lift components each beingdisposed laterally outside each of said feed side components; and saidnon-stop rails defining a frame surrounding at least portions of saidfeed side components.
 2. The sheet feed according to claim 1, whereinsaid frame includes said lift components.
 3. The sheet feed according toclaim 1, which further comprises guide rails mounted outside at saidfeed side components, said lift components being vertically shiftable insaid guide rails.
 4. The sheet feed according to claim 3, wherein saidfeed side components are feed side walls with upper edges, and whereinsaid guide rails of said lift components extend maximally up to saidupper edges of said respective feed side walls.
 5. The sheet feedaccording to claim 1, which further comprises support chains to whichsaid lift components are secured, and sprocket wheels driving saidsupport chains disposed laterally outside at said feed side components.6. The sheet feed according to claim 5, wherein said feed sidecomponents are sheet feed side walls, and at least one of said sprocketwheels is a driven sprocket wheel, and the other of said sprocket sheetsare deflector sprocket wheels.
 7. The sheet feed according to claim 6,which further comprises a common drive shaft connected between said atleast two driven sprocket wheels for fixing said at least two drivensprocket wheels against relative rotation.
 8. The sheet feed accordingto claim 1, wherein said feed side components are sheet feed side walls.9. The sheet feed according to claim 1, wherein said feed sidecomponents are sheet feed side walls with ends facing towards theprinting press, and said sheet feed side walls have apertures formedtherein at the ends thereof facing towards the printing press, and aforward portion of said frame, as seen in the direction of sheet feed,protruding through said apertures.
 10. The sheet feed according to claim1, wherein said frame is formed by a forward non-stop rail proximally ofthe printing press, two lateral frame portions extending along said feedside components, and a rear non-stop rail distally of the printingpress, said rear non-stop rail being removable from said frame.
 11. Thesheet feed according to claim 10, wherein said feed side components arefeed side walls, and wherein said rear non-stop rail is U-shaped, withtwo legs attaching to said lateral frame portions and extendingapproximately parallel to and laterally spaced apart from said feed sidewalls.
 12. The sheet feed according to claim 11, wherein said rearnon-stop rail has a rib between said two legs, said rib coveringrespective end faces of each of said feed side walls.
 13. The sheet feedaccording to claim 11, which further comprises lateral cover wallsdisposed laterally outside said feed side walls, said cover walls havingend faces distally of the printing press and voids formed in said endfaces for receiving said legs of said rear non-stop rail.
 14. The sheetfeed according to claim 13, wherein said rear non-stop rail is connectedinto said frame at connection points disposed laterally of said feedside walls, each said connection point being disposed inside a spacedefined between said respective lateral cover wall and said feed sidewall.
 15. The sheet feed according to claim 10, wherein said forwardnon-stop rail is secured to said lateral frame portions in floatingfashion.
 16. The sheet feed according to claim 10, wherein said rearnon-stop rail is secured to said lateral frame portions in floatingfashion.
 17. The sheet feed according to claim 11, which furthercomprises receiving mandrels formed on said lift components, and whereinsaid legs of said rear non-stop rail are hollow profile sections adaptedto be slipped onto said receiving mandrels.